Gotta love the Firebug console, how can anyone not love the Firebug console. It makes testing random pieces of JavaScript a breeze and best of all - you're playing with the live page. Your page or any page for that matter.

Two nice shortcuts you can use in the console are $ and $$.

The first is like document.getElementById() and the second allows you to get elements by using a selector, like w3c's document.querySelectorAll(), now available in the latest browser versions, including IE8.

So go ahead, give $$ a try. For example you can visit yahoo.com, open up the console and try:>>> $$('.first')
or>>> $$('.patabs .first')
or>>> $$('#tabs1 li')

Lots of fun!

So here's a little example application I came up with, it spits out unused selectors from your CSS. Just paste it in the multi-line console.